The primary objective of this research is to understand the mechanisms which control development. Chemotaxis and differentiation have been selected for study, particularly since these may have relevance to general development problems and hence related health problems. Identification of folic acid as a second chemotactic compound and elucidation of its minimum active component (pterin ring) has led to work showing various folic acid related compounds are secreted by the amoebae. Further studies already being actively pursued: (1) "degradation" of folic acid by amoebae, (2) identification and isolation of an acrasin for Polysphondylium since neither cyclic AMP nor folic acid appear to be the active compound. Cyclic AMP-induced differentiation has been previously demonstrated. (Bonner, 1970 PNAS). Using P-4, a mutant of Dictyostelium discoideum, stalk cell induction can be further studied. Since P-4 is more sensitive to cyclic AMP stalk induction, it can be made to resemble wild type by any method which increases phosphodiesterase. Projected work (in progress) includes: (1) secretion of cyclic AMP and phosphodiesterase; (2) structural comparison of P-4 and wild type stalk cells; (3) study on relation between protein synthesis and cyclic AMP effect; (4) assay of enzyme activities in P-4 treated with cyclic AMP.